Internal combustion engine with means for regulating the compression ratio



Jan. 3, 1939. K, TSUNEDAET AL 2,142,621

INTERNAL COMBUSTION ENGINE WITH MEANSA FOR REGrULATING4 THE CMPRESSION RATIO` Filed April 15, 1957 Patented Jan. 3, 1939 v I i I l I lUNITED STATES PATENT orrlcs A., 2,142,62'1 INTERNAL comms'rioN ENGINE wrm MEANS FOR REGULATING THE COMPRES- f i SION RATIO Application April 13, 1937, Serial No. 136,67 In Japan April 13, 1936 3 Claims. (CL 12H8) This invention relates to an internal combusconsumption is 4saved in the motor vehicle tion engine provided with means for varying the equipped with this invention. compression ratio, so that it is operated always Means for varying theV compression ratio ac at highest thermal eniciency under various coi-ding to this invention may be arranged in the 5 conditions cylinder'head, quite independently of the moving 5 In internal combustion engines of the Otto main part of the engine, sol that the operation or cycle type, the compression ratio is limited within the main part is by no means affected. Control a safety range so as to prevent advanced ignition of the liquid for actuating the movable member is or detonation even when operating under overeffected merely by openingor closing the passage load or when operating with the richest mixture of the circulating liquid, so that only'a slight 10 and at a considerably heated condition. "lhee-r power is required forthe purpose. and the confore, it is not possible under fullload to obtaintrol may be most effectively and. readily eiected. allowable maximum compression ratio. Under Moreover, by the circulation of'said liquid in the a lighter load, it is desirable that a higher comclosed chamber, cooling of the movable member 13 pression ratio be given in view of the decrease of may be also eiiected, whereby attaining a reliable l5 the amount of suction or dilution of the mixture. action of the movable member for varying the However, in an old engine with a xed volume of compression ratio. Any existing engine may be combustion chamber, it has been unavoidable readily re-constructed so as to be equipped with that, under lighter load, the compression ratio means of this invention by a simplework at -a greatly decreases below the maximum comprest low cost. 20

sion ratio allowed by the mixture then sucked in, The invention will ,now be fully described` with whereby the thermal efficiency of the engine is reference to the embodiment shown in the acconsiderably lowered. Especially for motor vehicompanying drawing, which shows in section acles, an engine having large output is used, in V-type multi-cylinder engine constructed accordview of the fact that quick acceleration is desiring to this invention. 25 able and that the vehicle must run with a com- The essential part of this invention comprises paratively high vspeed evenvon bad road or steep a movable member having behind it a liquid ascent road. O n the other hand, the majority of chamber, circulating means for supplying liquid the running period of the motor vehicle is on into and discharging from said chamber, and a flat road, in which period the engine is operated valve mechanism. for opening or closing the pas- 30 under a lighter load, about one-fourth of the full sages of thevsaid 'circulating liquid. v load, sov that it is unavoidable that there is loss Referring to the drawing, I designates a cylinof fuel consumption during such normal period der, 2 a cylinder head mounted thereon, and 3 0f running. is a piston. The cylinder head 2 is provided with This invention aims to remove the abovea cavity 4 opposite to the piston 3 and also facing 35 mentioned disadvantage, and it comprises a-proto the inlet valve 5 and exhaust valve (not vision of a movable member in the cylinder head shown). In said cavity 4 is slidably mounted a opposite the working piston of the engine, formpiston-like movable member 6. The movable ing a closed liquid chamber behind said movable member 6 is integrally formed with a central 40 member, and means for controlling the ow of barrel 1, of which the upper end isinserted into 40 liquid supplied into said closed chamber accorda boreiormed in .the upper end of the cavity l. ing to the working condition of the engine, so The lower end of thebarrel 'l is in communical that the position of said movable member is tion with the cavity 9 on `the rear side of the altered to vary the eilective lvolume of the commovable member 6. The cavity I, together with buStiOn chamber. BYSUCh means, it isv possible the movable member 6, forms a closed liquid45 t0 vary the Compression ratio aCCOIdBE t0 Variachamber.` 'Ihe upperwall of the liquid chamber tion of the load. the engine Speed. the mean is provided with a liquid outlet port ln.- working pressure, and the nature 0f fuel, ete.. s0 Upon the upper wall ofthe liquid chamber is 8S t0 aIWaYS Obtain highest thermal emciency mounted a valve casing II, in which are provided under lval'ymg Conditions Thus the thermal a liquid inlet valve I2 communicating with the 50 eiliciency iS increased under Vryig wndltins, -central barrel 1 and a check-valve I3 communi? and particularly under `a light load. The Inveneating with the liquid outlet port Ill. The liquid tion is most advantageously applicable for the inlet valve I2 is seated on a valve seat Il which engine for motor vehicles. By experiments it has is provided with a clearance in a portion so been found that approximately 30% o! the iuel thereof, and isv in communication with an inlet 55 lized as the liquid reservoir.

port I5' which is connected by means of a pipe l5 to a liquid reservoir I6. In the embodiment shown, the cooling jacket I6 of the engine is uti- In said pipe I5 is inserted a gear pump I1 which is actuated from thecrank-shaft I8 of the engine through any suitable transmission mechanism. The checkvalve I3 is connected by means of a pipe I9 to similar check-valve I3 provided on another cylinder. A liquid controlling valve 2| is provided in the port connecting said pipe I9 by means of conduit with the water cooling jacket I6.. In

the gear pump I'I is provided by-pass 24 which connects the outlet 22 and the inlet 23. In said by-Dass 24 is provided a pressure regulating valve 25 normally pressed toward the outlet 22.

Control of the liquid controlling valve 2| may be eiected manually as well as automatically. In the embodiment shown, it is automatically controlled through means responsive to variation of the vacuum in the intake pipe of the engine. Secured to the valve casing II, there is an airpressure case or short cylinder 2,6 having a central hollow post 21. Inserted through the bore of said post 21 is a valve presser Vrod 28 adapted to press the liquid controlling valve 2|. To the outer end of the rod.28 is secured a disc 29 pressed outwardly by a spring 30 against the outer closed end of a barrel 3I. Said barrel 3| has a working disc or piston 32 which is slidably mounted within the air-pressure cylinder 26 in an air-'tight manner. The air-pressure cylinder 26 is connected through a pipe 33 to the suction pipe 34 of the engine.

As the engine operates, the gear pump I 1 is also actuated, and the liquid in the Water cooling jacket I6 is normally forced into the space at the rear of themovable member 6 through the clearance left in the liquid inlet valve I2. The amount of the circulatingliquid thus forced into the liquid chamber behind the movable member varies according to the output of the engine. As it circulates, the temperature o f theliquid is lowered, and it acts to c'ool the movable member `6 and the adjacent portions.

In the no-load condition, as the degree of vacuum in the intake pipe 34 increases, the liquid controlling valve 2| behind the movable member 6 will be closed against the action of the maximum explosion pressure which acts upon the movable member 6, so that the ingress only of the liquid is permitted in the liquid chamber 9, discharge thereof being prevented by said closed valve 2|. Therefore, the movablemember 6 is gradually lowered, and it stops'when the highest compression ratio is obtained, and the circulation of the liquid is stopped. I When the engine output increases, the degree of vacuum in the intake pipe decreases according to.increase of the explosion pressure, and the liquid discharge valve 2| will be partly opened, permitting uid to flow through conduit 2IJ and into jacket I6, whereby the movable member 6 will be slightly moved upwardly during every explosion. On the other hand, the mo'vable member 6 receives a returning movement from'the liquid pressure supplied from the gear pump I1. Thus, the movable member 6 partakes up and down vibrating movement, while the liquid behind same is circulated. When the engine out' put is further increased,Y the liquid controlling valve 2| is opened wider, so that the distance' of the upward movement of the movable member 6 imparted by the explosion pressure exceeds Ithe distance of the downward return movement of the movable member Ii imparted by the pressure liquid, whereby the movable member during every cycle moves upwardly by a distance equal to the difference of said upward and downward movements. Thus, the compression ratio will gradually decrease, and the maximum explosion pressure will gradually decrease until the distance of the upward movement imparted to the movable member 6 by the explosion pressure becomes equal to the distance of the return movement imparted by the pressure liquid. Then, the movable member 6 will be merely vibrated at the position maintaining ,an intermediate compression ratio. the pressure liquid being circulated. When the load increases and the engine is operated for the full output, the degree of the vacuum in the intake pipe will become extremely weak, and the movable member 6 is rapidly moved upwardly, permitting the free discharge of'the pressure liquid behind the same, whereby it is maintained at the position of the lowest compression ratio, the pressure liquid being subjected to full circulation. In this condition, the discharge of the pressure liquid Vbeing fully permitted, the movable member 6 ceases to vibrate, and the pressure liquid freely flows into and out of the liquid chamber 9, solely s erving as the cooling means.

In. the multi-cylinder engine as shown in the drawing, only a single set of liquid circulating means and liquid controlling valve device is sufficient for the purpose, regardless of the number of cylinders, the liquid inlet port I5 and the checkvalve passage I9 for each cylinder being connected to each other. By such measure, it is possible to equalize the amount of pressure liquid supplied to all liquid chambers 9 behind the movable members 6 throughout the entire engine.

In order to attain smooth movement of the movable member 6 and to prevent leakage of the explosion gas, the sliding surface of the movable member 6 is preferably provided with suitable packings and piston ring 36 as shown in the drawing.

What we claim is:-`

1. An internal combustion engine with means for regulating the compression ratio, comprising a movable member facing to the combustion chamber, a closed chamber provided directly behind said movable member and filled with a pres-4 sure liquid, said closed liquid chamber being provided with liquid inlet and outlet ports connected with a liquid reservoir forming a liquid circuit, means inserted in said liquid circuit for circulating the pressure liquid, a controlling valve in said liquid circuit, and means responsive to engine voperation conditions for controlling said controlling valve for varying the amount of the pressure liquid in said closed liquid chamber behind the movable member. whereby varying the position ofthe latter. l

2. An internal combustion engine with means for regulating the-compression ratio, comprising a movable member facing to the combustion chamber, a closed chamber provided directly behind said movable member and lled with pressure water, said closed liquid chamber being provided with liquid inlet and outlet ports connected with an engine cylinder water jacket forming a liquid circuit, means inserted in said liquid circuit for circulating the pressurewater, a controlling valve in said liquid circuit, and means responsive to the vacuum in the intake pipe of the engine for controlling said controlling valve for varying the amount of the pressure liquid in said closed liquid chamber behind the movable member, whereby varying the position of the latter.

3. A multi-cyllnder internal combustion engine.

necting means for circulating the pressure liquid, a common controlling valve inserted in the liquid circuit including said closed chamberv and inlet and outlet ports, and' a common means for controlling said controlling valve, whereby the compression ratio is simultaneously regulated throughout all the cylinders.

KENJIRO TSUNEDA.

YASUSABURO HIRONAKA. 

